Data receiving devices, memory devices having the same, and operating methods thereof

ABSTRACT

A data receiving device of a memory device comprises a first pre-amplifier configured to receive previous data, a first reference voltage, and input data, and to output differential signals by comparing the input data with the first reference voltage in response to a clock, when the first pre-amplifier is selected in response to the previous data, a second pre-amplifier configured to receive inverted previous data, a second reference voltage, different from the first reference voltage, and the input data, and outputting a common signal in response to the clock, when the second pre-amplifier is unselected in response to the previous data; and an amplifier configured to receive the differential signals and the common signal, and to latch the input data by amplifying the differential signals.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a divisional of and claims priority from U.S.patent application Ser. No. 16/930,561, filed on Jul. 16, 2020, whichclaims the benefit of priority to Korean Patent Application No.10-2019-0163805, filed on Dec. 10, 2019 in the Korean IntellectualProperty Office, the disclosures of which are incorporated herein byreference in their entirety.

BACKGROUND 1 Field

The present disclosure relates to data receiving devices and memorydevices having the same.

2. Description of Related Art

In general, as semiconductor technology develops, a clock frequencyincreases and a data rate increases. Moreover, as the data rate betweena memory and a memory controller increases, distortion may occur in awaveform of data transmitted through a data channel. One of the causesof such distortion is intersymbol interference (ISI). ISI refers to aphenomenon in which previously-transmitted data affects transmissiondata currently transmitted due to a limitation of a bandwidth of a datachannel. One widely used technique for reducing the ISI effect is theuse of a decision feedback equalizer (DFE), which may be acircuit/filter that uses previous data (e.g., previous symbol decisions)to reduce ISI.

SUMMARY

An aspect of the present inventive concept is to provide a datareceiving device for reducing ISI, a memory device having the same, andan operating method thereof.

According to an aspect of the present inventive concept, a datareceiving device of a memory device may include: a first pre-amplifierreceiving previous data, a first reference voltage, and input data andoutputting differential signals by comparing the input data with thefirst reference voltage in response to a clock when the firstpre-amplifier is selected in response to the previous data; a secondpre-amplifier receiving inverted previous data, a second referencevoltage, different from the first reference voltage, and the input dataand outputting a common signal in response to the clock when the secondpre-amplifier is unselected in response to the previous data; and anamplifier receiving the differential signals and the common signal, andlatching the input data by amplifying the differential signals.

According to an aspect of the present inventive concept, a memory devicemay include: a memory cell array having a plurality of memory cells atintersections of a plurality of word lines and a plurality of bit lines;a row decoder selecting any one of the plurality of word lines inresponse to a row address; a bit line sense amplifying circuitconfigured to sense and to amplify data from selected ones of theplurality of memory cells during a reading operation; a column driverselecting bit lines among the plurality of bit lines in response to acolumn address; and a data input/output device receiving data from thebit line sense amplifying circuit during the reading operation, andreceiving input data from data pads during a writing operation. The datainput/output device may include at least one respective data input senseamplifier connected to each of the data pads, and the at least onerespective data input sense amplifier may include a first stage that isconfigured to output differential signals by amplifying the input datausing a reference voltage selected in response to previous data, and asecond stage that is configured to latch the input data by amplifyingthe differential signals.

According to an aspect of the present inventive concept, an operatingmethod of a data receiving device having a first stage and a secondstage may include receiving previous data from another data receivingdevice; activating a first pre-amplifier in response to the previousdata in the first stage; and amplifying differential signals output fromthe first pre-amplifier in the second stage.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view illustrating a data receiving device according to anexample embodiment of the present inventive concept;

FIGS. 2A and 2B are views illustrating pre-amplifiers according to anexample embodiment of the present inventive concept;

FIGS. 3A and 3B are views illustrating pre-amplifiers of a 3-stackstructure;

FIG. 4A is a view illustrating an amplifier according to an exampleembodiment of the present inventive concept;

FIG. 4B is a view illustrating an amplifier according to another exampleembodiment of the present inventive concept;

FIG. 5 is a view illustrating an operating timing diagram of the datareceiving device according to an example embodiment of the presentinventive concept;

FIG. 6A is a view illustrating an operating timing diagram of a firststage of the data receiving device according to an example embodiment ofthe present inventive concept, and FIG. 6B illustrates an operatingtiming diagram of a second stage of the data receiving device accordingto an example embodiment of the present inventive concept;

FIG. 7 is a view illustrating a memory device according to an exampleembodiment of the present inventive concept;

FIG. 8 is a view illustrating a memory device according to anotherexample embodiment of the present inventive concept;

FIG. 9 is a flowchart illustrating an operating method of a datareceiving device according to an example embodiment of the presentinventive concept;

FIG. 10 is a view illustrating a memory system according to an exampleembodiment of the present inventive concept; and

FIG. 11 is a view illustrating a mobile device according to an exampleembodiment of the present inventive concept.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present inventive concept willbe described clearly and in detail with reference to the accompanyingdrawings.

FIG. 1 is a view illustrating a data receiving device 100 according toan example embodiment of the present inventive concept. Referring toFIG. 1 , the data receiving device 100 may include a first pre-amplifier110, a second pre-amplifier 120, and an amplifier 130.

The first pre-amplifier 110 and the second pre-amplifier 120 maydetermine whether to select according to (e.g., in response to) previousdata DIN_PRE and DINB_PRE. That is, any one of the first pre-amplifier110 and the second pre-amplifier 120 may be selected according to theprevious data DIN_PRE and DINB_PRE, and the other may be unselected. Inthe following description, it is assumed that the first pre-amplifier110 is selected and the second pre-amplifier 120 is unselected forconvenience of description.

The first pre-amplifier 110 may be configured (i) to be selectedaccording to the previous data DIN_PRE, (ii) to compare data DIN with afirst reference voltage VREFUP in response to a clock CLK, and (iii) tooutput signals OUTF_UP and OUTFB_UP corresponding to a comparison result(i.e., in response to comparing the data DIN with the first referencevoltage VREFUP).

The second pre-amplifier 120 may be configured (a) to be selectedaccording to the inverted previous data DINB_PRE, (b) to compare dataDIN with a second reference voltage VREFDN in response to a clock CLK,and (c) to output signals OUTF_DN and OUTFB_DN corresponding to acomparison result. Here, the second reference voltage VREFDN may bedifferent from the first reference voltage VREFUP. For example, thesecond reference voltage VREFDN may be lower than the first referencevoltage VREFUP.

The amplifier 130 may be configured to receive any one of the outputsignals OUTF_UP and OUTFB_UP of the first pre-amplifier 110 and theoutput signals OUTF_DN and OUTFB_DN of the second pre-amplifier 120, andto output amplified data DINA in response to the received outputsignals.

As shown in FIG. 1 , the data receiving device 100 may be implementedwith two-stage sense amplifiers. A first stage is a circuit thatprovides amplification by any one of the first and second pre-amplifiers110 and 120, and a second stage is a circuit amplifying a signalamplified in the first stage.

The first stage may select a reference voltage according to the previousdata DIN_PRE and DINB_PRE. For example, the first reference voltageVREFUP may be selected according to the previous data DIN_PRE, and thesecond reference voltage VREFDN may be selected according to theprevious data DINB_PRE. Here, the previous data DIN_PRE and the previousdata DINB_PRE are complementary data. For example, when the previousdata DIN_PRE is ‘1’, the first preamplifier 110 may be activated, sothat the first reference voltage VREFUP may be selected in the firststage. In addition, when the previous data DINB_PRE is ‘1’, the secondpre-amplifier 120 may be activated, so that the second reference voltageVREFDN may be selected in the first stage. However, it should beunderstood that selection of the reference voltage in the first stage ofthe present inventive concept is not limited thereto.

In an example embodiment, the first stage may use a switch to remove(e.g., disconnect) a differential signal of one input pair without astack of transistors. An input pair transmitting a differential signalto the second stage may allow a current source to flow current first tohelp charge and drive an internal node.

The second stage may receive the differential signal of the first stageand amplify and output the corresponding data.

In general, DFE tap weight should be controllable over a constant andwide range for process, voltage, temperature (PVT) variations. In atwo-stage amplifier operating at a low voltage, a circuit performancemay be significantly degraded due to the stack of transistors. Thismakes it difficult to implement decision logic.

On the other hand, in the data receiving device 100 according to anexample embodiment of the present inventive concept, selection by theDFE operation can be implemented as/by a switch connected in parallel tothe input pair instead of a transistor connected in series. Non-idealoperating characteristics of this switch can be improved by weaklypre-charging the selected input pair.

FIGS. 2A and 2B are views illustrating pre-amplifiers 110 and 120according to an example embodiment of the present inventive concept.

Referring to FIG. 2A, a first pre-amplifier 110 may include currentsources IC1 and IC2, p-channel metal oxide semiconductor (PMOS)transistors PM1 and PM2, n-channel metal oxide semiconductor (NMOS)transistors NM1 and NM2, and a first switch SW1.

The first current source IC1 may be connected between a power supplyterminal VDD and a first node ND1. The second current source IC2 may beconnected between a power supply terminal VDD and a first node ND1.

The first PMOS transistor PM1 may have a source connected to the firstnode ND1, a drain connected to the second node ND2, and a gate forreceiving data DIN. The second PMOS transistor PM2 may have a sourceconnected to the first node ND1, a drain connected to the third nodeND3, and a gate for receiving a first reference voltage VREFUP. Thefirst NMOS transistor NM1 may be connected between a second node ND2 anda ground terminal GND in response to a clock CLK. The second NMOStransistor NM2 may be connected between a third node ND3 and a groundterminal GND in response to a clock CLK. The first switch SW1 mayconnect (or disconnect) the second node ND2 and the third node ND3 inresponse to the previous data DIN_PRE. Here, differential signalsOUTF_UP and OUTFB_UP of the first pre-amplifier 110 may be output fromthe second node ND2 and the third node ND3.

Meanwhile, a structure of the second pre-amplifier 120 may beimplemented in the same manner as the first pre-amplifier 110.

Referring to FIG. 2B, the second pre-amplifier 120 may include currentsources IC3 and IC4, PMOS transistors PM3 and PM4, NMOS transistors NM3and NM4, and a second switch SW2.

The third current source IC3 may be connected between a power supplyterminal VDD and a fourth node ND4. The fourth current source IC4 may beconnected between a power supply terminal VDD and a fourth node ND4. Thethird PMOS transistor PM3 may have a source connected to the fourth nodeND4, a drain connected to a fifth node ND5, and a gate for receivingdata DIN. The fourth PMOS transistor PM4 may have a source connected tothe fourth node ND4, a drain connected to a sixth node ND6, and a gatefor receiving a second reference voltage VREFDN. The third NMOStransistor NM3 may be connected between a fifth node ND5 and a groundterminal GND in response to a clock CLK. The fourth NMOS transistor NM4may be connected between a sixth node ND6 and a ground terminal GND inresponse to a clock CLK. The second switch SW2 may connect (ordisconnect) the fifth node ND5 and the sixth node ND6 in response to theprevious data DINB_PRE. Here, differential signals OUTF_DN and OUTFB_DNof the second pre-amplifier 120 may be output from the fifth node ND5and the sixth node ND6.

Meanwhile, the current sources IC1 to IC4 illustrated in FIGS. 2A and 2Bmay be implemented as (e.g., may comprise) transistors, and the switchesSW1 and SW2 may be implemented as (e.g., may comprise) transmissiongates.

FIGS. 3A and 3B are views illustrating pre-amplifiers 110 and 120 of a3-stack structure. Accordingly, each of the pre-amplifiers 110 and 120may have a respective 3-stack transistor structure rather than (i.e.,may be free of) any 4-stack transistor structure.

Referring to FIG. 3A, the first pre-amplifier 110 may include PMOStransistors PM1, PM2, PM5, and PM6, NMOS transistors NM1 and NM2, and afirst transmission gate TG1.

The first current source IC1 illustrated in FIG. 2A may include a fifthPMOS transistor PM5. Here, the fifth PMOS transistor PM5 may connect thepower supply terminal VDD and the first node ND1 in response to theprevious data DIN_PRE, thereby supplying current to the first and secondPMOS transistors PM1 and PM2. In addition, the second current source IC2illustrated in FIG. 2A may include a sixth PMOS transistor PM6. Here,the sixth PMOS transistor PM6 may connect the power supply terminal VDDand the first node ND1 in response to the clock CLK, thereby supplyingcurrent to the first and second PMOS transistors PM1 and PM2. Inaddition, the first switch SW1 illustrated in FIG. 2A may include afirst transmission gate TG1. Here, the first transmission gate TG1 mayconnect the second node ND2 and the third node ND3 in response to theprevious data DIN_PRE.

Referring to FIG. 3B, the second pre-amplifier 120 may include PMOStransistors PM3, PM4, PM7, and PM8, NMOS transistors NM3 and NM4, and asecond transmission gate TG2.

The third current source IC3 illustrated in FIG. 2B may include aseventh PMOS transistor PM7. Here, the seventh PMOS transistor PM7 mayconnect the power supply terminal VDD and the fourth node ND4 inresponse to the inverted previous data DINB_PRE, thereby supplyingcurrent to the third and fourth PMOS transistors PM3 and PM4. Inaddition, the fourth current source IC4 illustrated in FIG. 2B mayinclude an eighth PMOS transistor PM8. Here, the eighth PMOS transistorPM8 may connect the power supply terminal VDD and the fourth node ND4 inresponse to a clock CLK to supply current to the third and fourth PMOStransistors PM3 and PM4. In addition, a second switch SW2 illustrated inFIG. 2B may include a second transmission gate TG2. Here, secondtransmission gate TG2 may connect the fifth node ND5 and the sixth nodeND6 in response to the inverted previous data DINB_PRE.

Meanwhile, the pre-amplifiers 110 and 120 illustrated in FIGS. 3A and 3Bmay receive the previous data DIN_PRE and DINB_PRE as inputs, and mayselect one of the input pairs. After opening the correspondingtransmission gate, the selected pre-amplifier may output thedifferential signal to the amplifier 130. On the other hand, aftershorting the corresponding transmission gate, the unselectedpre-amplifier may filter out the differential signal.

Meanwhile, all of the output of the first stage may be transmitted tothe input of the second stage. The structure is a first pre-amplifierstage of the sense amplifier amplifying the data input at a small swinglevel rail-to-rail. The data low has a signal level obtained by adding acommon signal to a differential minus signal, and the data high has asignal level obtained by adding a common signal to a differential plussignal.

The first stage may sense the data input DIN and the reference voltagesVREFUP and VREFDN at a CLK falling edge, and amplify a detected voltagedifference and transfer the detected voltage difference to a latch ofthe second stage.

To compensate for ISI, the previous data DIN_PRE, DINB_PRE can activateone of the two input pairs. Activated input pairs can cause acorresponding transmission gate to have a turned off state. As a result,the input signals DIN and VREF may be amplified normally, therebydriving the second stage.

Inactivated input pairs can cause the corresponding transmission gate tohave a turned on state. A differential component of the input istherefore not transferred to the output. However, since each of theoutputs is pulled up to VDD, it can help drive the circuit itself. Inorder to transfer the signal of the activated input pairs to a nextstage first, the previous data DIN_PRE and DINB_PRE may pre charge theinternal node by partially driving a PMOS current source. Thus,differential signals that the transmission gate cannot completely removemay be separated in time.

Meanwhile, the pre amplifier stage of the present inventive concept mayselect a reference voltage advantageous for sensing according toprevious data DIN_PRE and DINB_PRE. In addition, the pre amplifier stageof the present inventive concept is advantageous for driving a lowvoltage because it does not use a method of selecting a referencevoltage by stacking transistors. In addition, input pairs not selectedby the DFE do not transfer the differential signal, but may help toincrease a bandwidth of a circuit by transferring the common signal used(e.g., required) for driving the next stage.

FIG. 4A is a view illustrating an amplifier 130 according to an exampleembodiment of the present inventive concept. Referring to FIG. 4A, theamplifier 130 may include PMOS transistors PM9 to PM14 and NMOStransistors NM5 to NM10.

The ninth PMOS transistor PM9 may include a source connected to thepower supply terminal VDD, a drain connected to the seventh node ND7,and a gate receiving an inverted feedback output signal OUTB_F. Thetenth PMOS transistor PM10 may include a source connected to the powersupply terminal VDD, a drain connected to the seventh node ND7, and agate connected to the eighth node NDB. The eleventh PMOS transistor PM11may include a source connected to the power supply terminal VDD, a drainconnected to the ninth node ND9, and a gate connected to the invertedfeedback output signal OUTB_F. The twelfth PMOS transistor PM12 mayinclude a source connected to the power supply terminal VDD, a drainconnected to the eighth node ND8, and a gate connected to the seventhnode ND7. The thirteenth PMOS transistor PM13 may include a sourceconnected to the power supply terminal VDD, a drain connected to theeighth node ND8, and a gate receiving a feedback output signal OUT_F.The fourteenth PMOS transistor PM14 may include a source connected tothe power supply terminal VDD, a drain connected to the tenth node ND10,and a gate connected to the feedback output signal OUT_F.

The fifth NMOS transistor NM5 may include a drain of the tenth PMOStransistor PM10, that is, a drain connected to the seventh node ND7, asource connected to the ninth node ND9, and a gate connected to theeighth node ND8. The sixth NMOS transistor NM6 may include a drainconnected to the ninth node ND9, a source connected to the groundterminal GND, and a gate receiving an inverted first differential signalOUTFB_UP. The seventh NMOS transistor NM7 may include a drain connectedto the ninth node ND9, a source connected to the ground terminal GND,and a gate receiving an inverted second differential signal OUTFB_DN.The eighth NMOS transistor NM8 may include a drain of the twelfth PMOStransistor PM12, that is, a drain connected to the eighth node ND8, asource connected to the tenth node ND10, and a gate connected to theseventh node ND7. The ninth NMOS transistor NM9 may include a drainconnected to the tenth node ND10, a source connected to the power supplyterminal GND, and a gate receiving a first differential signal OUTF_UP.The tenth NMOS transistor NM10 may include a drain connected to thetenth node ND10, a source connected to the power supply terminal GND,and a gate receiving a second differential signal OUTF_DN.

Meanwhile, final output signals DIN_0 and DINB_0 of the amplifier 130may be output from the seventh node ND7 and the eighth node ND8.

The amplifier 130 of the second stage may receive outputs of the firststage OUTF_UP, OUTF_DN, OUTFB_UP, and OUTFB_DN as inputs to drive thelatch.

One of OUTF_UP and OUTF_DN can drive the latch differentially with asignal selected by a DFE pass. In addition, the other one thereof maydrive a circuit in a common mode, since the first stage is switched on.

The drain of one NMOS transistor may be first pulled-down according tothe differential signal resulting from a difference in an input voltage,so that an inverter can be driven first. As the drains of both NMOStransistors may be pulled-down, the output of the cross-coupled latchcan be determined. The input signal can be amplified as a signal thatfinally moves rail-to-rail.

Meanwhile, in the amplifier 130 illustrated in FIG. 4A, each of theninth PMOS transistor PM9, the eleventh PMOS transistor PM11, thethirteenth PMOS transistor PM13, and the fourteenth PMOS transistor PM14may provide a power supply voltage to corresponding nodes ND7, NDB, ND9,and ND10 in response to corresponding feedback output signals OUT_F.However, the structure of the amplifier of the present inventive conceptis not necessarily limited thereto. The amplifier of the presentinventive concept may not include a transistor for performing a resetoperation of the node.

FIG. 4B is a view illustrating an amplifier 130 a according to anotherexample embodiment of the present inventive concept. Referring to FIG.4B, the amplifier 130 a may have a structure in which transistors PM9,PM11, PM13, and PM14, performing a node reset operation, compared to theamplifier 130 illustrated in FIG. 4A, are removed.

A conventional DFE structure compensates for ISI by selectively applyinga current to an input transistor of a sense amplifier according to adecision of a loop. However, this method varies current consumption ofthe sense amplifier according to an input difference and PVT variation.Thus, tap weight of DFE is not relatively constant.

By contrast, the DFE structure according to an example embodiment of thepresent inventive concept may compensate for ISI by using an inputreference voltage, thereby compensating the ISI more effectively andconstantly.

FIG. 5 is a view illustrating an operating timing diagram of the datareceiving device 100 according to an example embodiment of the presentinventive concept. Referring to FIG. 5 , in the case of a pattern of adata transition, ISI may be generated due to channel characteristics tocause a low swing. When the input data has an opposite output from theprevious data, a reference voltage can be selected to be advantageous.

FIG. 6A is a view illustrating an operating timing diagram of a firststage of the data receiving device 100 according to an exampleembodiment of the present inventive concept. Referring to FIG. 6A,low/high of the input data DIN may be primarily determined by performingan operation of the first stage at a falling edge of the clock CLK.

FIG. 6B is a view illustrating an operating timing diagram of a secondstage of a data receiving device 100 according to an example embodimentof the present inventive concept. Referring to FIG. 6B, an operation ofthe second stage may be performed on the output of the first stage, suchthat the low/high of the input data DIN may be finally determined. Asshown in FIG. 6B, the low or high of the input data DIN can be clearlydistinguished.

Meanwhile, the data receiving device 100 according to an exampleembodiment of the present inventive concept may be applied to a datainput sense amplifier DINSA (FIG. 7 ) of the memory device.

FIG. 7 is a view illustrating a memory device 200 according to anexample embodiment of the present inventive concept. Referring to FIG. 7, the memory device 200 includes a memory cell array 210, a row decoder220, a bit line sense amplifying (BLSA) circuit 230, a column decoder(e.g., column driver) 240, a data input/output circuit 250, andinput/output pads 260 (DQ1 to DQk, where k is an integer of 2 or more).

The memory cell array 210 may include at least one bank array. The atleast one bank array may include a plurality of memory cells disposed atintersections of the plurality of word lines and the plurality of columnlines. In an example embodiment, each of the plurality of memory cellsmay be a volatile or nonvolatile memory cell.

The row decoder 220 may be configured to select any one of the pluralityof word lines in response to the row address. That is, the row decoder220 may decode a row address output from the address buffer, and selecta word line corresponding to the row address in the data write/readmode. The address buffer may receive and store an address having a bankaddress, a row address, and a column address from an external memorycontroller. The address register may provide the received bank addressto the bank control logic, provide the received row address to the rowaddress multiplexer, and provide the received column address to thecolumn address latch.

The bit line sense amplifying circuit 230 may be configured tosense/amplify data of the selected memory cell. For example, the bitline sense amplifying circuit 230 may sense data by sensing/amplifyingthe bit line selected by the column decoder 240. In an exampleembodiment, the bit line sense amplifying circuit 230 may include aplurality of sense amplifiers.

The column decoder 240 may be configured to select a bit line connectedto a memory cell in response to a column address. That is, the columndecoder 240 may decode a column address output from the address buffer,and may select a bit line corresponding to the column address in a datawrite/read mode.

The data input/output circuit 250 may receive (amplify and latch) datafrom an external device through input/output pads DQ1 to DQk during awriting operation, and may transfer the received data to the bit linesense amplifying circuit 230. In addition, the data input/output circuit250 may receive data sensed by the sense amplifying circuit 230 frommemory cells corresponding to an address during a reading operation, andmay output the received data to an external device through theinput/output pads DQ1 to DQk.

In particular, the data input/output circuit 250 may include a pluralityof data input sense amplifiers DINSA and a data input/output buffer.

The data input sense amplifiers DINSA may be implemented by the datareceiving device described in FIGS. 1 to 6B and one or more operationsthereof.

The data input/output buffer may provide the data DQ to an errorcorrection circuit, based on a clock signal provided from the memorycontroller during the writing operation, and may provide the data DQfrom the error correction circuit to the memory controller during thereading operation. The error correction circuit may generate paritybits, based on data bits of the data DQ provided from the datainput/output buffers in a writing operation, and provide a codewordincluding the data DQ and the parity bits to the data input/outputcircuit 250. The data input/output circuit 250 may write a codeword tothe bank array. In addition, the error correction circuit may receive acodeword read from one bank array from the data input/output circuit 250in a reading operation. The error correction circuit may perform ECCdecoding on the data DQ using the parity bits included in the readcodeword and correct at least one error bit included in the data DQ toprovide the error bit to the data input/output buffer.

The control logic may be configured to control an overall operation ofthe memory device 200. The control logic may include a refresh controlcircuit, a command decoder, and a mode register circuit. The refreshcontrol circuit may receive a refresh signal decoded from the commanddecoder, and output an internal row address to the row decoder 220 torefresh one word line of the memory cell array 210. A command decodermay receive a command CMD (FIG. 10 ) from an external device (a memorycontroller), and may internally generate a command signal (for example,an active signal, a read signal, a write signal, a refresh signal, orthe like) decoded from the received command CMD. A mode register circuitmay set an internal mode register in response to a mode register set(MRS)/expended mode register set (EMRS) command for designating anoperating mode of the memory device 200. In addition, the mode registercircuit may output an activation signal responsive to the input/outputsignal to control an operation of the input/output circuit according tothe writing operation/reading operation.

Meanwhile, the data input/output circuit 250 illustrated in FIG. 7includes one data input sense amplifier DINSA on each input/output pad.However, the present inventive concept will not be limited thereto. Thememory device of the present inventive concept may include a pluralityof data input sense amplifiers corresponding to one input/output pad.

FIG. 8 is a view illustrating a memory device 200 a according to anotherexample embodiment of the present inventive concept. Referring to FIG. 8, the memory device 200 a includes a data input/output circuit 250 acomprising a plurality of data input sense amplifiers DINSA on one datapad as compared with that shown in FIG. 7 .

FIG. 9 is a flowchart illustrating an operating method of a datareceiving device according to an example embodiment of the presentinventive concept. Referring to FIGS. 1 to 9 , an operating method ofthe data receiving device 100 may proceed as follows.

The first stage (see FIG. 1 ) of the data receiving device 100 mayreceive data DIN and previous data DIN_PRE and DINB_PRE insynchronization with the clock CLK (S110). Here, the previous dataDIN_PRE and DINB_PRE may be received from another data receiving device.The pre-amplifier of the first stage may be activated/selected accordingto the received previous data DIN_PRE and DINB_PRE (S120). Thereafter,the second stage (see FIG. 1 ) of the data receiving device 100 mayperform a latching operation of the input data DIN by receiving andamplifying the differential signal from the activated pre-amplifier(S130).

The data receiving device 100 according to an example embodiment of thepresent inventive concept may include a 2-stage sense amplifier(double-tail sense amplifier) capable of selecting a reference voltageand operating with a low voltage.

The data receiving device 100 according to an example embodiment of thepresent inventive concept may use a switch to select an input pair and areference voltage to sense data without a stack of transistors.

The data receiving device 100 according to an example embodiment of thepresent inventive concept can quickly and reliably proceed to latchdriving by charging a differential signal to a node that receives aninput pair in a second stage by a current source in advance.

FIG. 10 is a view illustrating a memory system 1000 according to anexample embodiment of the present inventive concept. Referring to FIG.10 , the memory system 1000 may include at least one memory device 1100and a host device 1200 controlling the memory device 1100.

The host device 1200 may transmit a clock CLK, a command CMD, and anaddress ADD to store data in the memory device 1100 or read data storedin the memory device 1100. The host device 1200 may exchange data withthe memory device 1100 through a plurality of data lines DQ. Forexample, the host device 1200 may be a memory controller or a centralprocessing unit (CPU).

In an example embodiment, the host device 1200 may communicate with thememory device 1100 based on a graphics double data rate (GDDR)interface. However, as the present inventive concept is not limitedthereto, the host device 1200 may communicate with the memory device1100 based on at least one of various interfaces such as a universalserial bus (USB), a multimedia card (MMC), an embedded MMC (eMMC), aperipheral component interconnection (PCI), a PCI express (PCI-E), andan advanced technology attachment (ATA), serial-ATA, parallel-ATA, smallcomputer small interface (SCSI), enhanced small disk interface (ESDI),integrated drive electronics (IDE), firewire, a universal flash storage(UFS), a nonvolatile memory express (NVMe), or the like.

The memory device 1100 may store data received through the plurality ofdata lines DQ according to a control of the host device 1200, or maytransmit the stored data to the host device 1200 through the pluralityof data lines DQ. In an embodiment, the memory device 1100 may include adynamic random access memory (DRAM). However, as the present inventiveconcept is not limited thereto, the memory device 1100 may include atleast one of various memory devices such as static RAM (SRAM), dynamicRAM (DRAM), synchronous DRAM (SDRAM), read only memory (ROM),programmable ROM (PROM), electrically programmable ROM (EPROM),Electrically Erasable and Programmable ROM (EEPROM), a flash memorydevice, phase-change RAM (PRAM), magnetic RAM (MRAM), resistive RAM(RRAM), ferroelectric RAM (FRAM), or the like.

The memory device 1100 may include a data line driver 1110 configured tocontrol each of the plurality of data lines DQ. The DQ driver 1110 maygenerate a reference voltage or a reference voltage set for determiningdata provided through each of the plurality of data lines DQ.

In particular, the DQ driver 1110 may be implemented by the datareceiving apparatus 100 described in FIGS. 1 to 9 and one or moreoperations thereof.

Information about the reference voltage of each of the plurality of datalines DQ may be stored in a separate storage circuit (e.g., a code formin a mode register). The DQ driver 1110 may generate an internal codebased on the above-described code, and generate a reference voltage or areference voltage set based on the generated internal code. Codes forthe reference voltage of each of the plurality of data lines DQ may bedetermined during a training process for the memory device 1100.

FIG. 11 is a view illustrating a mobile device 3000 according to anexample embodiment of the present inventive concept. Referring to FIG.11 , the mobile device 3000 may include an application processor 3100,at least one DRAM 3200, at least one storage device 3300, at least onesensor 3400, a display device 3500, an audio device 3600, a networkprocessor 3700, and at least one input/output device 3800. For example,the mobile device 3000 may be implemented as a laptop computer, a mobilephone, a smartphone, a tablet personal computer, or a wearable computer.

The application processor 3100 may be configured to control an overalloperation of the mobile device 3000. The application processor 3100 mayexecute applications providing an internet browser, a game, a video, andthe like. In an example embodiment, the application processor 3100 mayinclude a single core or a multi-core. For example, the applicationprocessor 3100 may include a multi-core such as a dual-core, aquad-core, a hexa-core, and the like. In an embodiment, the applicationprocessor 3100 may further include a cache memory located internally orexternally.

The application processor (AP) 3100 may include a controller (CNTL)3110, a neutral processing unit (NPU) 3120, and an interface (IF) 3130.In an embodiment, the NPU 3120 may optionally be provided or omitted.

In an embodiment, the application processor 3100 may be implemented as asystem-on-chip (SoC). A kernel of an operating system that is driven ona system-on-chip (SoC) may include an input/output (I/O) scheduler and adevice driver for controlling the storage device 3300. The device drivermay control an access performance of the storage device 3300 byreferring to the number of sync queues managed by the input/output (I/O)scheduler, or may control a CPU mode inside a SoC, a dynamic voltage andfrequency scaling (DVFS) level, or the like.

The DRAM 3200 may be connected to the controller 3110. The DRAM 3200 maystore data used/necessary for an operation of the application processor3100. For example, the DRAM 3200 may temporarily store an operatingsystem (OS) and application data, or may be used as an execution spaceof various software codes.

DRAMs 3200 may be configured to receive data by a two-stage senseamplifier as described in FIGS. 1 to 10 . One of the DRAMs 3200 may havea relatively faster latency and bandwidth (BW) than I/O devices or flashmemory. The DRAM 3200 may be initialized at the time of mobile power-on,and the OS and application data may be loaded and used as a temporarystorage location of the OS and application data, or may be used as anexecution space of various software codes. The mobile system performs amultitasking operation of simultaneously loading several applications,and switching between applications and an execution speed can be used asa performance index of the mobile system. A second DRAM 3200 may beconnected to NPU 3120. That DRAM 3200 may store data related toartificial intelligence operation(s).

The storage device 3300 may be connected to the interface 3130. In anexample embodiment, the interface 3130 may be operated by onecommunication protocol of DDR, DDR2, DDR3, DDR4, low power DDR (LPDDR),universal Serial bus (USB), a multimedia card (MMC), embedded MMC,peripheral component interconnection (PCI), non-volatile memory express(NVMe), peripheral component interconnect express (PCIe), serialadvanced technology attachment (SATA), small computer system interface(SCSI), serial attached SCSI (SAS), universal storage bus ((USB)attached SCSI (UAS)), an internet small computer system interface(iSCSI), fiber channel and fiber channel over ethernet (FCoE). In anexample embodiment, any one of the storage devices 3300 may be includedin the mobile device 3000 in an embedded form. In another exampleembodiment, any one of the storage devices 3300 may be included in themobile device 3000 in a detachable manner.

The storage device 3300 may be configured to store user data. Forexample, the storage device 3300 may store data collected from thesensor 3400, or may store data network data, augmented reality(AR)/virtual reality (VR) data, and high definition (HD) 4K content. Thestorage device 3300 may include at least one nonvolatile memory device.For example, the storage device 3300 may include a solid state driver(SSD), an embedded multimedia card (eMMC), and the like.

In an example embodiment, the storage device 3300 may be implemented asa separate chip in the application processor 3100, or may be implementedas one package with the application processor 3100.

In an example embodiment, the storage device 3300 may be mounted usingvarious types of packages. For example, the storage device 3300 may bemounted using packages such as a package on package (PoP), ball gridarrays (BGAs), chip scale packages (CSPs), a plastic leaded chip carrier(PLCC), a plastic dual in-line package (PDIP), Die in Waffle Pack, Diein Wafer Form, a chip on board (COB), a ceramic dual in-line package(CERDIP), a plastic metric quad flat pack (MQFP), a thin quad flatpack(TQFP), small outline integrated circuit (SOIC), a shrink small outlinepackage (SSOP), a thin small outline package (TSOP), a system in package(SIP), a multi chip package (MCP), a wafer-level fabricated package(WFP), a wafer-level processed stack package (WSP), or the like.

The sensor 3300 may be configured to sense an external environment ofthe mobile device 3000. In an example embodiment, the sensor 3300 mayinclude an image sensor sensing an image. In this case, the sensor 3300may transmit the generated image information to the applicationprocessor 3100. In another example embodiment, the sensor 3300 mayinclude a biosensor sensing biometric information. For example, thesensor 3300 may sense a fingerprint, an iris pattern, a blood vesselpattern, a heart rate, a blood sugar, and the like, and generate sensingdata corresponding to the sensed information. Meanwhile, it should beunderstood that the sensor 3300 is not limited to the image sensor andthe biosensor. The sensor 3300 of the present inventive concept mayinclude any sensor, such as an illuminance sensor, an acoustic sensor,an acceleration sensor, or the like.

The display device 3500 may be configured to output data. For example,the display device 3500 may output image data sensed using the sensor3300 or output data calculated using the application processor 3100.

The audio device 3600 may be configured to output voice data to theoutside (i.e., outside of the mobile device 3000) or detect externalvoice.

The network processor 3700 may be configured to connect communicationwith an external device by a wired or wireless communication method

The input/output device 3800 may be configured to input data to oroutput data from the mobile device 3000. The input/output device 3800may include devices providing digital input and output functions such asan USB or a storage, a digital camera, an SD card, a touch screen, aDVD, a modem, a network adapter, and the like.

A decision feedback equalizer (DFE) circuit according to an exampleembodiment of the present inventive concept may have a small swing levelof the input signal, and the DFE circuit can be applied to a productthat needs/benefits from equalizing because ISI is generated by channelcharacteristics.

The DFE circuit according to an example embodiment of the presentinventive concept may use two reference voltages for a 2-stage senseamplifier.

The DFE circuit according to an example embodiment of the presentinventive concept may use a differential signal bypassing method througha switch during a selection process of the DFE.

The DFE circuit according to an example embodiment of the presentinventive concept may drive a selected input pair in advance by drivinga current source according to a DFE decision.

As set forth above, according to an example embodiment of the presentinventive concept, a data receiving device, a memory device having thesame, and an operating thereof may comprise a two-stage sense amplifieroutputting different differential signals according to previous data,thereby improving a data receiving operation.

Various advantages and effects of the present inventive concept are notlimited to the above description. While example embodiments have beenshown and described above, it will be apparent to those skilled in theart that modifications and variations could be made without departingfrom the scope of the present disclosure, as defined by the appendedclaims.

What is claimed is:
 1. A memory device comprising: a memory cell arrayhaving a plurality of memory cells at intersections of a plurality ofword lines and a plurality of bit lines; a row decoder configured toselect any one of the plurality of word lines in response to a rowaddress; a bit line sense amplifying circuit configured to sense and toamplify data from selected ones of the plurality of memory cells duringa reading operation; a column driver configured to select bit linesamong the plurality of bit lines in response to a column address; and adata input/output device configured to receive data from the bit linesense amplifying circuit during the reading operation, and to receiveinput data from data pads during a writing operation, wherein the datainput/output device includes at least one respective data input senseamplifier connected to each of the data pads, and wherein the at leastone respective data input sense amplifier includes a first stage that isconfigured to output differential signals by amplifying the input datausing a reference voltage selected in response to previous data, and asecond stage that is configured to latch the input data by amplifyingthe differential signals.
 2. The memory device of claim 1, wherein thefirst stage includes: a first pre-amplifier configured to output thedifferential signals to the second stage in response to the previousdata; and a second pre-amplifier configured to output a common signal tothe second stage in response to the previous data.
 3. The memory deviceof claim 2, wherein each of the first and second pre-amplifierscomprises a respective 3-stack transistor.
 4. The memory device of claim1, wherein the second stage comprises a cross-coupled sense amplifierthat is configured to receive the differential signals.
 5. The memorydevice of claim 1, wherein the at least one data input sense amplifierincludes: a first data input sense amplifier that is configured toreceive the input data; and a second data input sense amplifier that isconfigured to store the previous data.